These valuations are typically required for your insurance provider and are an assessment of the rebuilding cost of the property which reflects the construction type and includes all ancillary features like roadways, gardens, stores etc.
Such assessments are carried out in accordance with Royal Institute of Chartered Surveyors (RICS) guidance on both houses and blocks of flats.
Most leases for blocks of flats require a regular updating of valuations based upon accurate rebuilding figures. This is usually required every 3 years.
Having an incorrect figure on your Insurance file could result in a reduced pay-out in the event of a claim.